Container systems for mixing fluids with a magnetic stir bar

ABSTRACT

A container system includes a substantially rigid container having a floor and a side wall upstanding therefrom. The side wall and floor bound a chamber. A magnetic mixer is disposed below the floor of the container. A mixing bag assembly is disposed within the chamber of the container. The mixing bag assembly includes a collapsible body having a first end and an opposing second end. The collapsible body bounds a compartment. A mixing dish is disposed at the second end of the collapsible body so as to communicate with the compartment thereof. A magnetic stir bar is disposed on the mixing dish.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 10/797,159, filed on Mar. 10, 2004, which claimspriority to U.S. Provisional Patent Application Ser. No. 60/458,677,filed on Mar. 28, 2003 which are incorporated herein by specificreference.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention relates to container systems for mixing andstoring fluids.

2. The Relevant Technology

The mixing and/or suspension of solutions is ubiquitous in manytechnologies. For example, biotech companies use extensive amounts ofculture media, buffers, and reagents. Such materials originally come inpowdered form and must be hydrated with purified water prior to use. Thehydration process typically comprises combining a precise amount ofpowdered material and purified water in a closed stainless steel tank. Aspecial mixer is then used to mix the components into the desiredsolution. Liquid supplements can be added before or after the initialmixing. Once the solution is prepared, the solution is filtered and maybe directly used or dispensed and sealed into sterile containers forshipment or storage.

To be safe and effective for their intended use, solutions of culturemedia, buffers, and reagents must be pure and sterile. Accordingly,between the production of different batches of solutions, the mixingtank, mixer, and all other reusable components that contact the solutionmust be carefully cleaned to avoid any cross contamination. The cleaningof the structural components is labor intensive, time consuming, andcostly. For example, depending on the structural component and thesolution being produced, cleaning can require the use of chemicalcleaners such as sodium hydroxide and may require steam sterilization aswell.

In another example, the production of vaccines or the culturing of cellstypically requires that such solutions be continually mixed so that thecomponents thereof remain uniformly dispersed as a homogeneous solution.Again, however, although steel tanks and mixers can be used to maintainsuch suspension and dispersion, conventional systems require that thetanks and mixers be carefully cleaned between batches to avoid any crosscontamination.

Accordingly, what is needed in the art are container systems whichminimize the time, cost, and labor associated with cleaning andsterilizing conventional systems while enabling mixing and/or suspensionof solutions.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be discussed withreference to the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope.

FIG. 1 is a perspective view of a container system;

FIG. 2 is a partially exploded perspective view of a portion of thecontainer system shown in FIG. 1;

FIG. 3 is a cross sectional side view of the system shown in FIG. 2without the lid thereof;

FIG. 4 is a cross sectional side view of the mixing bag assembly shownin FIG. 1;

FIG. 5A is a perspective view of the panels of the mixing bag assemblyshown in FIG. 4;

FIG. 5B is a perspective view of the panels shown in FIG. 5A seamedtogether;

FIG. 6 is a perspective view the mixing dish, retention plate, and stirbar shown in FIG. 4; and

FIG. 7 is a cross sectional side view of the container system shown inFIG. 1 taken along section line 7-7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to container systems that enable a user tohydrate powders, suspended components of a liquid, and/or otherwise mixsolutions without the need for extensive cleaning of the systems betweenbatches. The container systems of the present invention can be used inassociation with culture media, buffers, reagents and other solutionscommonly used in the biotech industry and can also used in associationwith a vast array of other solutions outside of the biotech industry.

Depicted in FIG. 1 is one embodiment of a container system 10incorporating features of the present invention. In general, containersystem 10 includes a substantially rigid container 12 seated on a dolly14. Disposed within container 12 is a mixing bag assembly 16. Disposedbetween mixing bag assembly 16 and dolly 14 is a magnetic mixer 18 (FIG.2). As will be discussed below in greater detail, magnetic mixer 18 isused to mix a solution disposed within mixing bag assembly 16.

As depicted in FIG. 2, container 12 comprises a substantiallycylindrical side wall 24 that extends from an upper end 26 to anopposing lower end 28. As depicted in FIG. 3, container 12 includes afloor 30 formed inside of container 12 at a position between upper end26 and lower end 28. Floor 30 has a substantially frustaconicalconfiguration. More specifically, floor 30 has top surface 74 thatextends between an inner edge 70 and an opposing outer edge 76. Inneredge 70 bounds a central opening 72 extending through floor 30. Outeredge 76 is integrally formed with or is otherwise connected to side wall24.

For example, in the embodiment depicted side wall 24 comprises an outerwall 50 that extends between opposing ends 26 and 28 and an inner wall51 that extends from a central portion 31 of floor 30 to lower end 28.An annular transition 52 connects outer wall 50 and inner wall 51 atlower end 28. Above transition 52, outer wall 50 and inner wall 51 arespaced apart so as to form an annular gap 53. An annular seal 55 isdisposed within gap 53 so as to form a bridge between outer wall 50 andinner wall 51 at the location where inner wall 51 connects with centralportion 31 of floor 30. Seal 55 combines with central portion 31 to formfloor 30. In part, seal 55 functions to prevent mixing bag assembly 16from sliding into gap 53 which could cause failure of mixing bagassembly 16.

In this embodiment, container 12 is molded so that outer wall 50, innerwall 51, transition 52, and central portion 31 of floor 30 are allintegrally formed as a single mold item. In alternative embodiments,inner wall 51 and seal 55 can be eliminated. This can be accomplished byintegrally molding floor 30 directly to outer wall 50 or by having adiscrete floor 30 that is connected to outer wall 50.

Top surface 74 of floor 30 slopes radially outward and upward from inneredge 70 to outer edge 76. Floor 30 thus functions in part as a funnel todirect all material toward central opening 72. In alternativeembodiments, floor 30 can be flat, cupped, irregular, or other desiredconfigurations.

Side wall 24 of container 12 has an interior surface 32 disposed abovefloor 30. Interior surface 32 and floor 30 bound a first chamber 34formed in upper end 26 of container 12. First chamber 34 can be sized tohave any desired volume. For example, first chamber 34 can be sized tohold 50 liters, 100 liters, 200 liters, or other desired amounts.Depicted in FIG. 2, upper end 26 of container 12 terminates at an upperedge 42 that bounds an opening 44 to first chamber 34. An optionalannular lid 46 can be removably disposed over upper edge 42 so as toselectively close opening 44. Clamps 48 are used to selectively securelid 46 to container 12.

Returning to FIG. 3, side wall 24 also has an interior surface 36 formedbelow floor 30. Interior surface 36 and floor 30 bound a second chamber38 disposed at lower end 28 of container 12. An access port 40 extendsthrough side wall 24 at lower end 28 of container 12 so as to provideside access to second chamber 38. In alternative embodiments, theportion of side wall 24 extending below floor 30 can be replaced withone or more spaced apart legs or other supports that elevate floor 30off of the ground, dolly 14, or other surface on which container 12rests.

In the embodiment depicted, container 12 comprises a barrel molded froma polymeric material. In alternative embodiments, container 12 can becomprised of metal, fiberglass, composites, or any other desiredmaterial. Furthermore, although container 12 is shown as having asubstantially cylindrical configuration, container 12 can besubstantially boxed shaped or have a transverse configuration that ispolygonal, elliptical, irregular, or any other desired configuration.

As depicted in FIG. 2, dolly 14 comprises a frame 54 having a pluralityof wheels 56 mounted thereon. Dolly 14 enables easy movement ofcontainer 12. In alternative embodiments where it is not necessary ordesired to move container 12, wheels 56 and/or frame 54 can beeliminated. In this regard, container 12 can sit on a ground surface orany other desired structure.

Magnetic mixer 18 is mounted on dolly 14. Magnetic mixer 18 is astandard off-the-shelf item that uses a magnetic force to rotate amagnetic stir rod which will be discussed below in greater detail. Oneexample of magnetic mixer 18 comprises the MAXISTIRRER Model #S25530240V available from Barnstead/Thermolyne out of Dubuque, Iowa. Magneticmixer 18 has a top surface 60 and a front face 62. Switches 64 arepositioned on front face 62 and are used for turning magnetic mixer 18on and off and for adjusting the speed at which magnetic mixer 18rotates a magnetic stir bar.

Depicted in FIG. 3, lower end 28 of container 12 is received on dolly 14such that magnetic mixer 18 is received with second chamber 38 directlybelow central opening 72 of floor 30. Container 12 is oriented such thataccess port 40 of container 12 is aligned with front face 62 of magneticmixer 18. As a result, a user can reach through access port 40 forselectively activating and controlling magnetic mixer 18.

Depicted in FIG. 4 is a cross sectional side view of mixing bag assembly16. Mixing bag assembly 16 comprises a flexible and collapsible bag-likebody 80 having an interior surface 82 and an exterior surface 84.Interior surface 82 bounds a compartment 86. More specifically, body 80comprises a side wall 88 that, when body 80 is unfolded, has asubstantially circular or polygonal transverse cross section thatextends between a first end 90 and an opposing second end 92. First end90 terminates at a top end wall 94 while second end 92 terminates at abottom end wall 96.

Body 80 is comprised of a flexible, water impermeable material such aspolyethylene or other polymeric sheets having a thickness in a rangebetween about 0.1 mm to about 5 mm with about 0.2 mm to about 2 mm beingmore common. Other thicknesses can also be used. The material can becomprised of a single ply material or can comprise two or more layerswhich are either sealed together or separated to form a double wallcontainer. Where the layers are sealed together, the material cancomprise a laminated or extruded material. The laminated materialcomprises two or more separately formed layers that are subsequentlysecured together by an adhesive.

The extruded material comprises a single integral sheet which comprisestwo or more layer of different material separated by a contact layerthat are all simultaneously co-extruded. Once example of an extrudedmaterial that can be used in the present invention is the HyQ CX5-14cast film available from HyClone Laboratories, Inc. The HyQ CX5-14 castfilm comprises a polyester elastomer outer layer, an ultra-low densitypolyethylene contact layer, and an EVOH barrier layer disposedtherebetween. Another example of film that can be used is the Attanefilm which is also available from HyClone Laboratories, Inc. The Attanefilm is produced from three independent webs of blown film. The twoinner webs are a 4 mil monolayer polyethylene film, while the outerbarrier web is a 5.5 mil thick 6-layer coextrusion film.

In one embodiment, the material is approved for direct contact withliving cells and is capable of maintaining a solution sterile. In suchan embodiment, the material can also be sterilizable such as by ionizingradiation. Other examples of materials that can be used are disclosed inU.S. Pat. No. 6,083,587 which issued on Jul. 4, 2000 and U.S. patentapplication Ser. No. 10/044,636, filed Oct. 19, 2001 which are herebyincorporated by specific reference.

In one embodiment, body 80 comprises a two-dimensional pillow style bagwherein two sheets of material are placed in overlapping relation andthe two sheets are bounded together at their peripheries to forminternal compartment 86. Alternatively, a single sheet of material canbe folded over and seamed around the periphery to form internalcompartment 86. In the embodiment depicted, however, body 80 comprises athree-dimensional bag which not only has an annular side wall 88 butalso a two dimensional top end wall 94 and a two dimensional bottom endwall 96.

Three dimensional body 80 comprises a plurality, i.e., typically threeor more, discrete panels. Depicted in FIG. 5A, body 80 is comprised offour panels, i.e., top panel 98, front panel 99, back panel 100, andbottom panel 101. Each panel 98-101 has a substantially square orrectangular central portion 104. Top panel 98 and bottom panel 101include a first end portion 106 and an opposing second end portion 108projecting from opposing ends of central portion 104. Each of endportions 106 and 108 has a substantially trapezoidal configuration withopposing tapered edges 110. Front panel 99 and back panel 100 eachinclude a triangular first end portion 107 and an opposing triangularsecond end portion 109 projecting from opposing ends of central portion104.

As depicted in FIG. 5B, corresponding perimeter edges of each panel98-101 are seamed together so as to form a substantially box shaped body80. Panels 98-101 are seamed together using methods known in the artsuch as heat energies, RF energies, sonics, other sealing energies,adhesives, or other conventional processes. It is appreciated that byaltering the size and configuration of some or all of panels 98-101,body 80 can be formed having a variety of different sizes andconfigurations. It is also appreciated that any number of panels can beused to adjust the size and configuration of body 80.

In still other embodiments, it is appreciated that body 80 can be formedby initially extruding or otherwise forming a polymeric sheet in theform of a continuous tube. In one embodiment, the tube can simply be cutto length and each end seamed closed to form a two-dimensional pillowstyle bag. In an alternative embodiment, each end can be folded like theend of paper bag and then seamed closed so as to form a three dimensionbody. In still another embodiment, a length of tube can be laid flat soas to form two opposing folded edges. The two folded edges are theninverted inward so as to form a pleat on each side. The opposing end ofthe tube are then seamed closed. Finally, an angled seam is formedacross each corner so as to form a three dimensional bag when inflated.

It is appreciated that the above techniques can be mixed and matchedwith one or more polymeric sheets and that there are still a variety ofother ways in which body 80 can be formed having a two or threedimensional configuration. Further disclosure with regard to one methodof manufacturing three-dimensional bags is disclosed in U.S. patentapplication Ser. No. 09/813,351, filed on Mar. 19, 2001 of which thedrawings and Detailed Description are hereby incorporated by specificreference.

It is appreciated that body 80 can be manufactured to have virtually anydesired size, shape, and configuration. For example, body 80 can beformed having compartment 86 sized to hold 50 liters, 100 liters, 200liters, or other desired amounts. Although body 80 is depicted in FIG.5B having a substantially box shaped configuration, body 80, as depictedin FIG. 4, conforms to the configuration of first chamber 34 as it isfilled with solution. In one embodiment, however, body 80 can bespecifically configured to be complementary or substantiallycomplementary to first chamber 34.

In any embodiment, however, it is desirable that when body 80 isreceived within first chamber 34, body 80 is uniformly supported byfloor 30 and side wall 24 of container 12. Having at least generallyuniform support of body 80 by container 12 helps to preclude failure ofbody 80 by hydraulic forces applied to body 80 when filled with asolution.

As depicted in FIG. 4, mounted on top end wall 94 of body 80 are a pairof spaced apart ports 112 and 114. Each port 112 and 114 comprises abarbed tubular stem 116 having a flange 118 outwardly projecting from anend thereof. During assembly, a pair of spaced apart holes are madethrough top panel 98 (FIGS. 5A and B) prior to complete seaming togetherof panels 98-101. The stem 116 of each port 112 and 114 is then passedthrough a corresponding hole until flange 118 rests against panel 98.Conventional welding or other sealing techniques are then used to sealeach flange 118 to panel 98. During use, stem 116 is selectively coupledwith a tube or container for delivering material into and/or out ofcompartment 86. It is appreciated that any number of ports can be formedon body 80 and that a variety of different types and sizes of ports canbe used depending on the type of material to be dispensed intocompartment 86 and how the material is to be dispensed therefrom.

Mounted on bottom end wall 96 of body 80 is a mixing dish 120. Asdepicted in FIGS. 4 and 6, mixing dish 120 comprises a substantiallyflat floor 122 and an annular outer perimeter flange 124. Asubstantially frustaconical side wall 126 encircles floor 122 andoutwardly and upwardly extends to perimeter flange 124. Side wall 126includes an annular first shoulder 128 and an annular second shoulder130. Side wall 126 and floor 124 bound a cavity 132. Inwardly projectingfrom side wall 126 directly above second shoulder 130 are a plurality ofspaced apart catches 134.

As with ports 112 and 114, during assembly a hole 103 is formed inbottom panel 101 (FIG. 5A). Mixing dish 120 is seated within hole 103 sothat outer perimeter flange 124 rests against bottom panel 101. Again,conventional welding or other sealing techniques are then used to sealperimeter flange 124 to bottom panel 101.

An annular retention plate 136 bounds a plurality of openings 138extending therethrough. Retention plate 136 is removably attached tomixing dish 120 by pushing retention plate 136 onto second shoulder 130so that retention plate 136 is caught between second shoulder 130 andcatches 134. Due to openings 138 formed on retention plate 136, cavity132 is in fluid communication with compartment 86 of body 80.

In one embodiment, mixing dish 120 is integrally molded from a polymericmaterial, such as high density polyethylene, and has a thickness in arange between about 1 mm to about 5 mm. Mixing dish 120 is more rigidthan body 80 and in one embodiment is substantially rigid so as toprevent unwanted bending or flexing during use.

Disposed within cavity 132 of mixing dish 120 and resting on floor 122thereof is a conventional off-the-shelf magnetic stir bar 140. Stir bar140 is typically sold as a unit with magnetic mixer 18 and is configuredto selectively rotate within cavity 132 under the control of magneticmixer 18. That is, magnetic mixer 18 controls the speed and variabilityat which stir bar 140 rotates.

Once ports 112, 114 and mixing dish 120 are sealed to theircorresponding panel and stir bar 120 is captured within mixing dish 120by retention plate 136, panels 98-1 01 are seamed together so as tocomplete the formation of bag 80 and bag assembly 16. During use, asdepicted in FIG. 7, mixing bag assembly 16 is disposed within firstchamber 34 of container 12 so that floor 122 of mixing dish 120 isreceived within central opening 72 extending through floor 30 ofcontainer 12. Annular first shoulder 128 of mixing dish 120 supportsmixing dish 120 on floor 30 of container 12. In this configuration,floor 122 of mixing dish 120 is disposed above or directly on topsurface 60 of magnetic mixer 18.

Tubes or containers are then coupled to at least one of ports 112 and114 for delivering a solution or components for a solution intocompartment 86 of mixing bag assembly 16. At least one of the componentscan be a substantially dry material such as a powder, granule, or otherform of dry material. Alternatively, all of the components can beliquid. Once the solution or components are within compartment 86 ofmixing bag assembly 16, magnetic mixer 18 is activated so that magneticstir bar 140 is rotated within mixing dish 120. In turn, stir bar 140mixes the solution or components within compartment 86. Depending on theselected speed of magnetic mixer 18, stir bar 140 can form a vortexwithin the solution.

Side wall 126 of mixing dish 120 and retention plate 136 in partfunction to retain stir bar 140 within cavity 132 during transport ofmixing bag assembly 16 and the initial activation of magnetic mixer 18.That is, stir bar 140 will often jump around as magnetic mixer 18 isinitially activated. Side wall 126 and retention plate 136 help tomaintain stir bar 140 within cavity 132 until it obtains smoothrotation. The flat and substantially rigid floor 122 of mixing dish 120assists in expediting the rate as which stir bar 140 moves into a smoothrotation.

Depending on the type of solution being mixed, the solution can beselectively drawn out of mixing bag assembly 16 either while the mixingis occurring and/or after completion of the mixing and magnetic mixer 18is turned off. Once the solution is removed, mixing bag assembly cansimply be disposed of such as by being discarded or recycled. A newmixing bag assembly 16 is then inserted within container 12 and theprocess can be repeated for a new batch of solution. As a result, notank or mixer cleaning is required between different batches and thereis no risk of cross contamination. Of course where cross contaminationis not a concern, mixing bag assembly 16 can be used repeatedly fordifferent batches until the assembly is worn or a non-compatible batchis to be made.

In alternative embodiments, it is appreciated that mixing dish 120 cancome in a variety of alternative configurations. For example, retentionplate 136 is not required but can produce some functional benefits.Furthermore, mixing dish 120 need not be bowl shaped but can comprise asubstantially flat plate. In this embodiment, floor 30 of container 12can be sufficiently tapered to help ensure that stir bar 140 remains onthe mixing dish. In yet other embodiments of the present invention, itis noted that central opening 72 can be eliminated on floor 30 ofcontainer 12, i.e., a flat section of floor 30 can extend across prioropening 72. In this embodiment, mixing dish 120 sits directly on theflat section of floor 30 above magnetic mixer 18.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

1. A mixing bag assembly comprising: a body bounding a compartment, thebody being comprised of a flexible sheet; a mixing dish secured to thebody, the mixing dish having a floor in communication with thecompartment of the body; and a magnetic stir bar disposed on the floorof the mixing dish.
 2. The mixing bag assembly as recited in claim 1,wherein the body comprises a two-dimensional pillow style bag or a threedimensional bag.
 3. The mixing bag assembly as recited in claim 1,wherein the body comprises at least three polymeric panels seamedtogether.
 4. The mixing bag assembly as recited in claim 1, wherein themixing dish further comprises an annular side wall upstanding from thefloor, the side wall terminating at a perimeter edge, the perimeter edgebeing secured to the body.
 5. The mixing bag assembly as recited inclaim 1, wherein the mixing dish is more rigid than the body.
 6. Themixing bag assembly as recited in claim 1, wherein the mixing dish issubstantially rigid.
 7. The mixing bag assembly as recited in claim 1,wherein the mixing dish comprises a substantially flat plate secured tothe body.
 8. The mixing bag assembly as recited in claim 1, furthercomprising at least one fluid port mounted on the body so as tocommunicate with the compartment of the body.
 9. The mixing bag assemblyas recited in claim 1, wherein the compartment of the body has a volumeof at least 50 liters.
 10. The mixing bag assembly as recited in claim1, wherein the body has a hole extending therethrough, the mixing dishbeing at least partially disposed within the hole and secured to thebody.
 11. The mixing bag assembly as recited in claim 1, wherein themixing dish has an interior surface and an opposing exterior surface, atleast a portion of the interior surface being in communication with thecompartment of the body, at least a portion of the exterior surface notbeing in communication with the compartment of the body.
 12. The mixingbag assembly as recited in claim 1, wherein the mixing dish is sealed tothe body.
 13. A container system comprising: a substantially rigidcontainer having a floor and an upper side wall upstanding therefrom,the upper side wall and floor bounding a first chamber; a magnetic mixerdisposed below the floor of the container; and a mixing bag assembly atleast partially disposed within the first chamber of the container, themixing bag assembly comprising: a collapsible body bounding acompartment, the body having a first end and an opposing second end, atleast a portion of the second end of the body resting on or adjacent tothe floor of the container, a mixing dish being more rigid than thecollapsible body, the mixing dish being secured at the second end of thecollapsible body; and a magnetic stir bar disposed on the mixing dish.14. The container system as recited in claim 13, wherein the floor isintegrally formed with the upper side wall of the container.
 15. Thecontainer system as recited in claim 13, wherein at least a portion ofthe mixing dish is resting on the floor of the container.
 16. Thecontainer system as recited in claim 13, wherein the floor has anopening extending therethrough, at least a portion of the mixing dishextending through the opening on the floor.
 17. The container system asrecited in claim 13, wherein mixing dish is disposed directly on oradjacent to the magnetic mixer.
 18. The container system as recited inclaim 13, wherein the upper side wall of the container terminates anedge bounding a top opening, a lid being removably mounted on the upperside wall so as to cover the top opening.
 19. The container system asrecited in claim 13, wherein the body of the mixing bag comprises atwo-dimensional pillow style bag or a three dimensional bag.
 20. Thecontainer system as recited in claim 13, wherein the body of the mixingbag is comprised of a laminated or extruded polymer sheet comprised totwo or more layers of different material.
 21. The container system asrecited in claim 13, wherein the mixing dish comprises an annular sidewall extending between a floor and a perimeter edge, the perimeter edgebeing secured to the body.
 22. The container system as recited in claim13, wherein the body of the mixing bag has a hole extendingtherethrough, the mixing dish being at least partially disposed withinthe hole and secured to the body.
 23. The container system as recited inclaim 13, wherein the mixing dish has an interior surface and anopposing exterior surface, at least a portion of the interior surfacebeing in communication with the compartment of the body, at least aportion of the exterior surface not being in communication with thecompartment of the body.
 24. A mixing bag assembly comprising: a bodybounding a compartment, the body being comprised of at least oneflexible sheet; a mixing dish assembly at least partially disposed onthe body and at least partially bounding a cavity, at least one openingbeing formed on the mixing dish assembly so as to provide fluidcommunication between the cavity of the mixing dish assembly and thecompartment of the body; and a magnetic stir bar disposed within thecavity of the mixing dish assembly.
 25. The mixing bag assembly asrecited in claim 24, wherein the at least one opening on the mixing dishis sized so as to prevent the magnetic stir bar from freely passing fromthe cavity to the compartment.
 26. The mixing bag assembly as recited inclaim 24, wherein at least a portion of the mixing dish assembly issecured to the body.
 27. A method comprising: inserting a disposablemixing bag assembly within a substantially rigid container, thecontainer having a floor with an opening extending therethrough, amagnetic stir bar being disposed within a compartment of the mixing bagassembly so that the stir bar is aligned with the opening on the floorof the container; delivering a solution or at least two separatecomponents into the compartment of the mixing bag assembly, at least oneof the at least two separate components being a liquid; and activating amagnetic mixer disposed below the opening on the floor-of the containerso as to cause rotation of the magnetic stir bar within the mixing bagassembly, the magnetic stir bar stirring the solution or the at leasttwo separate components.
 28. The method as recited in claim 27, furthercomprising dispensing from the mixing bag assembly the solution or theat least two components that are stirred within mixing bag assembly. 29.The method as recited in claim 27, wherein the mixing bag assemblycomprises: a body bounding the compartment, the body being comprised ofat least one flexible sheet; and a mixing dish secured to the body, themixing dish having a floor with the magnetic stir bar disposed thereon,the act of inserting comprising at least partially positioning themixing dish within the opening on the floor of the container.